The DMI was not affected by the addition ofWBG to the diets
(P>0.05, Table 3). Moreover, when urea was used to partially
replace SBM, no differences inDMI were observed (P>0.05).
Milk yield increased linearly as WBG was fed (P0.05). However, milk protein yield
tended to have quadratic response as WBG increased in the
diet (P=0.06). The addition of 2 % of urea decreased milk
protein content (P=0.04) and milk protein yield (P=0.01). In
addition, plasma urea nitrogen increased with 2%of urea (P=
0.02). Milk lactose content, total solid content, plasma glucose
concentration, and BW variation were not affected by the
treatments (P>0.05). Milk lactose yield (P=0.01) and milk
total solid yield (P=0.04) increased linearly with WBG addition.
The higher urea content decreased milk lactose and total
solid yields (P=0.05) compared to control and also decreased
milk yield. Feed efficiency responded quadratically to WBG
content (P=0.04)